The present invention relates to a tube clamp assembly for flexible tubing and, more particularly, to a tube clamp assembly for holding different sizes of flexible tubing to be used in a peristaltic pump.
Peristaltic pumps have been widely used for medical and research applications where constant or pulsatile metering of fluids at a relatively low flow rates is desired. Peristaltic pumps are volumetric pumps which progressively compress a flexible tube to propel a fluid along the tube under the influence of rotating members which contact the tube at spaced-apart locations. More specifically, the conventional peristaltic pump provides a circular array of rollers which are driven in a planetary motion against one or more flexible tubes to effect the compression thereof and the resultant pumping of the fluid. Such pumps are commonly used in cardiovascular surgery for circulating blood between a patient and a heart-lung machine. Other common uses for such pumps are the transfer of blood between a patient and a kidney dialyser and the intravenous infusion of medications.
In pumps which utilize peristaltic tubes, or an array of peristaltic tubes, special care must be taken to assure that the tubes deliver fluid at the desired rate. The rate of delivery is a function not only of the rate at which the rollers move along the tube, but also of the inside and outside diameters of the tube, the compression characteristics, the force with which the roller compresses the tube and the tension of the tube within the pump. All these variables must be carefully and precisely controlled to assure consistent and uniform or pulsatile metering rates within and between the delivery tubes.
One of the most easily changed variables in a peristaltic pump is the diameter of the flexible tubing through which the fluid is pumped. Typical tubing varies from an outer diameter of 0.213xe2x80x3 to 0.6875xe2x80x3, although tubing have greater and lesser diameters is also known. A tubing clamp is utilized in order to accommodate this wide range of tubing sizes in the peristaltic pump, and the clamp is typically configured to receive a clamp insert corresponding to the desired tubing size. Not only does this require a set of clamp inserts to be maintained for all possible tubing sizes, increasing the costs associated with the peristaltic pump, but changing the clamp insert also increases the time and labor required for operating room preparation.
In addition, although clamps do exist that can be adjusted to hold a limited range of tubing sizes without changing an insert, these clamps may often require an additional tool such as a wrench in order to effect the tubing size adjustment and, once again, greatly increase the time and labor required for operating room preparation
A strong need therefore exists for a tubing clamp capable of holding a plurality of sizes of flexible tubing without requiring additional set up time or labor intensive manipulation of clamp inserts or adjustments.
In order to overcome these disadvantages, the present invention provides a clamp assembly for flexible tubing having a housing, at least one movable slide disposed within the housing, an opening defined between the slide and the housing for receiving flexible tubing, and a control element. Rotation of the control element in a first direction displaces the slide in a first predetermined direction, and thereby opens the opening for insertion of flexible tubing. In a preferred embodiment of the invention, each movable slide includes opposing slide elements and each of the slide elements includes a slide recess. Similarly, the housing includes two opposing side supports and each of the side supports includes a support recess. Thus, each opening is defined between the slide recess in the slide and the support recess in the housing.
In a preferred embodiment of the present invention, the control element includes a control knob and an internal surface of the control element includes a cam surface. Each movable slide also includes a cam element which engages a cam surface on the control element. Thus, rotation of the control knob results in movement of the cam surface and the cam element engaged therewith, thereby displacing the movable slide.
A further embodiment of the present invention is directed to a clamp assembly for flexible tubing including a housing, an upper movable slide disposed within the housing, a lower movable slide disposed within the housing that is disposed vertically beneath the upper slide, a plurality of tubing openings defined between the slides and the housing, and a rotatable control element. Rotation of the control element displaces the slides in a predetermined lateral direction. Each of the movable slides includes a slide element which has a slide concavity. Similarly, the housing includes two opposing side supports, each of which includes an upper concavity generally aligned with the slide concavity of the upper movable slide and a lower concavity generally aligned with the slide concavity of the lower movable slide. Accordingly, the plurality of tubing openings are defined between the slide concavities and the upper and lower housing concavities.
The present invention also includes a method of clamping a plurality of flexible tubing including the step of providing a clamp assembly having a housing, at least one movable slide disposed within the housing, openings defined between each side of at least one slide and the housing for receiving flexible tubing, and a control element. The method further includes rotating the control element in a first direction from a neutral position so as to open the opening on first side of the clamp assembly, inserting flexible tubing through the opening, rotating the control element in a second direction, opposite to the first direction, to return to the neutral position, and thereby closing the opening to engage the flexible tubing.